According to the Dodd stopwatch...

From NBC's Mark Murray
Here are the final times each campaign received, per the Dodd campaign: Obama spoke the longest (16:00 minutes); Gravel the shortest (5:37).

Biden: 7:58      10 questions
Clinton: 14:26   15 questions
Dodd: 8:28         9 questions
Edwards: 11:42     13 questions
Gravel: 5:37     10 questions
Kucinich: 9:02    9 questions
Obama: 16:00    16 questions
Richardson: 10:48    11 questions